What Does Benzoyl Peroxide in Acne Treatments Do?

Benzoyl peroxide is an ingredient used to treat mild to moderate acne in products like Proactiv. Often combined with other acne treatments, it works as a peeling agent to increase skin turnover and clear pores.

How Does Benzoyl Peroxide Work?

Propionibacteria acnes, or P. acnes, are the bacteria that cause acne breakouts. Because they cannot live in an aerobic (oxygen-rich) environment, benzoyl peroxide introduces oxygen into the pore to kill P. acnes. This oxidizing power also dries out thickened sebum or fluid within the acne to help it heal without having to pop the acne. When the amount of bacteria is reduced, the number of breakouts on the skin is reduced as well.

In addition, benzoyl peroxide helps the hair follicle get rid of excess dead skin cells. By clearing the pores, it helps to prevent breakouts before they start, as there is less of a chance of blockages or comedones. Its anti-inflammatory properties also reduce swelling in infected papules and pustules to provide relief from the soreness that often comes with acne outbreaks.

While benzoyl peroxide is effective on its own, it can deliver even better results when used in conjunction with other acne-fighting ingredients or regimens, such as those found in Proactiv.

What Forms is Benzoyl Peroxide Available In?

There are many benzoyl peroxide products available, many of which can be purchased without a prescription though certain cleansers, foams, or lotions may require one. Proactiv is a dermatologist-developed over-the-counter acne solution, which contains benzoyl peroxide and does not require a prescription.

Most commonly available in a gel or cream form, benzoyl peroxide is typically applied to the affected areas of skin in concentrations of 2.5% through 10%. While it may seem that the higher percentage formulations would work better, research shows that higher concentrations of benzoyl peroxide are not significantly more effective than solutions with 2.5%, and the lower dosage is usually better tolerated on the skin.

Directions for Using Benzoyl Peroxide

Start with a cleanser, lotion, or gel solutions in a 2.5% strength to allow your skin to become acclimated to the benzoyl peroxide treatments. Follow the instructions provided with your acne regimen, though most commonly, directions would include applying a thin layer of benzoyl peroxide over thoroughly cleansed and dried skin once or twice daily. It is not meant to be used as a spot treatment, but as part of a comprehensive solution.

You should continue to use benzoyl peroxide even after acne clears up. Once you stop, bacterium populations can increase and acne may return. To determine how long you should use your acne treatments, contact your dermatologist.

Possible Side Effects

While side effects may initially include dryness and irritation, the skin will develop a tolerance after a week or so. Many dermatologists recommend applying the lowest concentration of benzoyl peroxide at first and build up from there. Any dryness or flaking that occurs can also be reduced by using a daily oil-free moisturizing lotion. Since it does tend to dry out the skin, some redness and peeling should be expected.

Avoid getting benzoyl peroxide into your eyes, inside your nose or mouth, or on any areas of broken skin, since it can cause irritation. Flush with plenty of water if this does indeed happen. And, try to avoid anything that might irritate the skin such as abrasive skin products, heavy cosmetics, alcohol, or prolonged exposure to sunlight.

Other Common Uses for Benzoyl Peroxide

In the U.S., the typical concentration of benzoyl peroxide in acne treatment is 2.5% to 10% for both over-the-counter and prescription uses. Higher concentrations are used for hair bleach and teeth whitening. Like most peroxides, benzoyl peroxide is a bleaching agent, so contact with fabrics or hair can cause color changes almost immediately. Use caution when applying it to your skin and avoid contact with hair, clothing, and furnishings.